In certain cases the old barter system can be beneficial to both parties - free takeaways aren't going to pay off the overdraft but they will put food on the table.
For it to work for you, you need to be getting their service at cost value, eg you get the same value in ingredients as you're giving in materials, you work 'for free' and his chefs cook the ingredients 'for free'.
You'd need to establish whether this was his intention or if he wanted to pay you in terms of what he's charging, eg you charge £200, he effectively gives you a £200 curry voucher, which at around £10 a pop would only give you 20 curries.
Personally I eat for around £2 per meal at home, so those 20 curries would only be saving me about £40, or in other words the deal would leave me £160 worse off.
Depends how much you like takeaway curry I suppose.
